ZModeler3 core has changed related to scene objects and materials. This involves re-writing of import/export code in each filter. I've ported the very minimum of requirement. GTA5 yft files are different to GTA4 wft and these are barely could be used inside one code block. So i'm working on gta5 yft filter only and gta4 wft will stay in zmod2 only.

you can save .z3d file inside zmodeler2 and load this file in zmodeler3. Several simple steps to re-configure materials and you get something very-alike to what you had in zmod2 initially.